Dear Wentao,

 Please consult

https://sites.math.rutgers.edu/~zeilberg/Hist21/q8S.pdf

for the full solutions.

You got 5 points (out of 10). Here is what you got wrong:

#2: -1 point (day laborer NOT a buisnessman)

#4: -4 points


 Best wishes,

   Dr. Z.